And as one commenter underneath my post put it, sarcastically: "Let's all condemn those parents who try to teach their children that swearing, lying, cheating, bullying etc are wrong – and have some time in the last 30 years failed to maintain the standard themselves." It's true, we wouldn't necessarily condemn such a parent. But there are important differences.

For a start, the "sinner that repenteth" defence falls down if you've kept your "sins" a secret. An ex-smoker warning us of the dangers of smoking is fine – but an ex-smoker who told us that smokers were nasty black-lunged cancer-spreaders but had led us to believe, through commission or omission, that he had never touched a cigarette, would get a few raised eyebrows. A Lefty education minister who sent her kids to private school might be OK, but if she told us that sending your kids to private school is terrible while not telling us where she'd sent her own (even if they are now grown up) would be rightly castigated. A mum who told her kids not to swear and pretended she'd never so much as said "damn" would lose credibility if a child found her effing and blinding at a cold-caller.

Cardinal O'Brien apparently was homosexually active, and later in life told us that being homosexually active is morally disordered. That might not be hypocritical in itself, but if he wants to avoid accusations of cover-up and hypocrisy, admitting that you have in fact practised what you're preaching against would be a good start.

But the real reason these "anti-gay activist turns out to be gay" stories get the attention is that they're so regular, so inevitable, as the Hitchens quote ably demonstrates. I don't know of any other area of moralising which leads so regularly from one to the other: anti-drug campaigners usually don't later turn out to have been secretly doing meth, anti-drink-driving campaigners are rarely sneaking off to have a few and drive home. Gun control activists tend not to carry concealed weapons.

But as Prof Richard M Ryan, the author of that NY Times piece, says, and as I should really have remembered before posting that somewhat crowing Hitch quote, simply shouting "hypocrisy" is somewhat to miss the point: "at least some who oppose homosexuality are likely to be individuals struggling against parts of themselves, having themselves been victims of oppression and lack of acceptance. The costs are great, not only for the targets of anti-gay efforts but also often for the perpetrators. We would do well to remember that all involved deserve our compassion."

So. I don't think it's unfair to call Cardinal O'Brien a hypocrite; his secrecy about his own homosexual behaviour, combined with his fervour about the immorality of others', opens him up to that charge. But I do agree with Prof Ryan: the cardinal has clearly struggled for years with something that he, wrongly, believes is a terrible part of himself, and has taken that struggle out on others. That doesn't make it right, but it does make it understandable, and deserving of compassion.